Cutting tools used in CNC machines are made to nominal sizes but rarely measure the precise size they were designed to.
The precision machining of components serving many industries becomes more and more demanding. Computerized Numerical Control, or CNC, Machine Tools are becoming more advanced, software programming is becoming more powerful, and new cutting tools grow in user acceptance based on their particular strategy. Throughout all of these continuing improvements with technology, the one variable that is often overlooked is that a nominal size tool does not always measure its designed precise size.
Precise work pieces can be manufactured with the use of CNC machines. These machines are very accurate and precise. A CNC machine tool has three linear axes of motion while more advanced CNC machine tools are four axis, five axis, or more. CNC machine tools have become very advanced and repeat toolpath positions well within 0.0002″ (two ten-thousandths of an inch).
Machine tool programming software plays a vital role in achieving efficient tool paths in CNC machines. To achieve efficient tool paths accurate tool paths must be programmed at the machine or through offline CAM (Computer-Aided Manufacturing) software. CNC programs, or tool paths, are primarily based off of the size of tool specified. Tool paths have accuracy to or finer than 0.0002″ (two ten-thousandths of an inch).
Tooling used in machining centers has rapidly grown in size and shape. Specific tool geometry meets certain criteria to achieve specific tool path strategies. These tools are more commonly made from high speed steel, cobalt, and carbide. Tools can be made from one solid material, or component. Tools may also have two or more materials, or components, commonly known as indexable tools. Tools are designed to standard nominal sizes in both imperial and metric units.
With the investment of a CNC machine, CAM software, and dedicated tooling, machinists expect high quality results to precisely machine components. However this is not always the result.
More often than not a tool does not measure the exact nominal size of its design. Software continues to apply paths correctly within 0.0002″, the machine tool continues to repeat a toolpath within 0.0002″, but the cutting tool is more commonly the variable and the reason behind low quality results.
Tools are not easy to measure with hand instruments. Tools have very fine cutting edges, sometimes an odd number of flutes, or sometimes variable flute geometry . . . just to name a few. Tools very rarely measure their nominal size within 0.0002″ (two ten-thousandths of an inch).
Some CNC machines offer an electronic means to measure a tool however they will not always identify the condition of a tool with multiple flutes.